/*
 * Copyright (c) 2018-2020 "Graph Foundation,"
 * Graph Foundation, Inc. [https://graphfoundation.org]
 *
 * This file is part of ONgDB.
 *
 * ONgDB is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
/*
 * Copyright (c) 2002-2020 "Neo4j,"
 * Neo4j Sweden AB [http://neo4j.com]
 *
 * This file is part of Neo4j.
 *
 * Neo4j is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
package org.neo4j.shell.apps.extra;

import java.io.File;
import java.io.IOException;
import java.io.Serializable;
import java.lang.reflect.Method;
import java.rmi.RemoteException;
import java.util.Map;

import org.neo4j.shell.Output;

/**
 * Executes groovy scripts purely via reflection
 */
public class GshExecutor extends ScriptExecutor
{
    private static final String BINDING_CLASS = "groovy.lang.Binding";

    private static final String ENGINE_CLASS = "groovy.util.GroovyScriptEngine";

    @Override
    protected String getDefaultPaths()
    {
        return super.getDefaultPaths() + ":" +
                "src" + File.separator + "main" + File.separator + "groovy";
    }

    @Override
    protected String getPathKey()
    {
        return "GSH_PATH";
    }

    @Override
    protected void runScript( Object groovyScriptEngine,
        String scriptName, Map<String, Object> properties, String[] paths )
        throws Exception
    {
        properties.put( "out", new GshOutput( (Output) properties.get( "out" ) ) );
        Object binding = this.newGroovyBinding( properties );
        Method runMethod = groovyScriptEngine.getClass().getMethod(
            "run", String.class, binding.getClass() );
        runMethod.invoke( groovyScriptEngine, scriptName + ".groovy",
            binding );
    }

    private Object newGroovyBinding( Map<String, Object> properties )
        throws Exception
    {
        Class<?> cls = Class.forName( BINDING_CLASS );
        Object binding = cls.newInstance();
        Method setPropertyMethod =
            cls.getMethod( "setProperty", String.class, Object.class );
        for ( String key : properties.keySet() )
        {
            setPropertyMethod.invoke( binding, key, properties.get( key ) );
        }
        return binding;
    }

    @Override
    protected Object newInterpreter( String[] paths )
        throws Exception
    {
        Class<?> cls = Class.forName( ENGINE_CLASS );
        return cls.getConstructor( String[].class ).newInstance(
            new Object[] { paths } );
    }

    @Override
    protected void ensureDependenciesAreInClasspath() throws Exception
    {
        Class.forName( BINDING_CLASS );
    }

    /**
     * A wrapper for a supplied {@link Output} to correct a bug where a call
     * to "println" or "print" with a GString or another object would use
     * System.out instead of the right output instance.
     */
    public static class GshOutput implements Output
    {
        private Output source;

        GshOutput( Output output )
        {
            this.source = output;
        }

        @Override
        public void print( Serializable object ) throws RemoteException
        {
            source.print( object );
        }

        @Override
        public void println( Serializable object ) throws RemoteException
        {
            source.println( object );
        }

        @Override
        public Appendable append( char c ) throws IOException
        {
            return source.append( c );
        }

        @Override
        public Appendable append( CharSequence csq, int start, int end )
            throws IOException
        {
            return source.append( csq, start, end );
        }

        @Override
        public Appendable append( CharSequence csq ) throws IOException
        {
            return source.append( csq );
        }

        /**
         * Prints an object to the wrapped {@link Output}.
         * @param object the object to print.
         * @throws RemoteException RMI error.
         */
        public void print( Object object ) throws RemoteException
        {
            source.print( object.toString() );
        }

        @Override
        public void println() throws RemoteException
        {
            source.println();
        }

        /**
         * Prints an object to the wrapped {@link Output}.
         * @param object the object to print.
         * @throws RemoteException RMI error.
         */
        public void println( Object object ) throws RemoteException
        {
            source.println( object.toString() );
        }
    }
}
